对称性强制双重 Weyl 点、多带量子几何以及费米能级掺杂诱导态的奇异平带
Symmetry-enforced double Weyl points, multiband quantum geometry, and singular flat bands of doping-induced states at the Fermi level
AI总结：
针对拓扑材料特征远离费米能级且能带过宽的难题，提出通过规则掺杂降低晶格对称性以在费米能级诱导非平庸拓扑态，构建模型揭示双重 Weyl 点与奇异平带等特征，并结合 DFT 计算验证其在多种材料中的普适性。
摘要：
设计拓扑量子材料时的两个常见困难是：所需特征离费米能级太远，且分布在过大的能量范围内。费米能级处的掺杂诱导态提供了一种解决方案，其中非平庸的拓扑性质由掺杂降低的对称性所强制产生。为了展示这一点，我们考虑在空间群（SG）176（$P6\ ext{}_3/m$）的晶格中规则放置掺杂原子，从而将对称性降低至 SG 143（$P3$）。我们的双带和四带模型具有双重 Weyl 点、Chern 带、Van Hove 奇点、由混合轨道特性导致的非平庸多带量子几何，以及奇异平带。我们将这些特征与密度泛函理论（DFT）计算相联系，研究对象包括铅磷灰石 Pb$_{10}($PO$_4)_6$O 和 Pb$_{10}($PO$_4)_6($OH$)_2$、范德华铁磁体 Cr$_2$Ge$_2$Te$_6$、半导体 SiC 以及二维二硫族化合物 MoS$_2$ 的掺杂和空位能带。
英文摘要：
Two common difficulties in the design of topological quantum materials are that the desired features lie too far from the Fermi level and are spread over a too-large energy range. Doping-induced states at the Fermi level provide a solution, where nontrivial topological properties are enforced by the doping-reduced symmetry. To show this, we consider a regular placement of dopants in a lattice of space group (SG) 176 ($P6\text{}_3/m$), which reduces the symmetry to SG 143 ($P3$). Our two- and four-band models feature double Weyl points, Chern bands, Van Hove singularities, nontrivial multiband quantum geometry due to mixed orbital character, and singular flat bands. We relate these features to density-functional theory (DFT) calculations for dopant and vacancy bands of lead apatite Pb$_{10}($PO$_4)_6$O and Pb$_{10}($PO$_4)_6($OH$)_2$, the van der Waals ferromagnet Cr$_2$Ge$_2$Te$_6$, the semiconductor SiC, and the 2D dichalcogenide MoS$_2$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
